5 Answers
5

While not always appropriate, bulleted lists naturally take care of the nesting problem. In addition, they help individualize the reading experience by allowing the reader to drill down into interesting areas while skipping others.

The park has:

bears

grizzlies, which number in the tens

Attacks are much rarer than the media would lead you to believe, but they do happen.

brown bears, which number in the thousands

many deer, which are quite friendly, like to eat camp food, and watch visitors

The park has: some bears; many deer, like roe deer which are quite friendly, like to eat camp food, and watch visitors — also fallow deer which are timid; and other animals, most of which live in the trees.

That would work, but it's awkward and although a dash seems to work, you can really only have one of those and it's still very easy to get lost in the lists. I would separate the detail into another sentence. You can add further detail like this quite easily.

The park has: some bears; many deer; and other animals, most of which live in the trees. The park's roe deer are quite friendly, like to eat camp food and watch visitors; the fallow deer are quite timid. Tree-dwelling animals include chimpanzees, which can be quite fierce; and macaques, which are rarely seen at all.

I'm not sure about the last semi-colon in that example. (Oh, and I usually use deer.)